I’m not sure that is the case either. Don’t scientists gather ”facts’ and represent the ”facts’ of their studies in addition to their conclusions, if any? If a scientist conducts a test and writes down that when the test started there were 1mil bacterium per millimeter and when the test was concluded there were on average 10mil bacterium per millimeter, is that really not referred to as ”facts’ within science? Sure it may more typically be called data or datum.
Even odder to me, is that if the claim is that there are no facts in science and that science has no definition for fact. If that is the case, then logically, the common definition of fact would actually apply to science. Sure scientists can say that internally they do not use nor define the term (if this is actually the case), but if they have no internal definition, then the external definition applies.
Still even odder to me is the assertion that fact somehow means 100% certainty. This definition is not one I have ever seen used. I can’t think of a single where a ”fact’ is objectively 100% certain.
We need to keep in mind that "fact" and "prove" are part of common language. They are not technical terms within science, although "prove" is a technical term in mathematics. When a scientist is using math, he would probably use "prove" in the strict mathematical sense. At other times, he might use "fact" and "prove" with the same sloppiness we see in ordinary speech.
Precision of language works both ways. To me it is far more misleading for people to say that evolution hasn’t been proved or hasn’t been upheld to be factual when clearly the question being asked is not defining the terms in the same way.